Battery operated timing device

ABSTRACT

There is disclosed a portable writing board comprising a flat board having a size and shape to be conveniently supported upon a limb of the user and adapted to receive paper thereon for writing purposes, timing apparatus mounted on the board for producing a train of timing pulses at an output therefor, a first timing pulse counter mounted on the board and including an input and an indicator output, a second timing pulse counter mounted on the board and including an input and an indicator output, and switching apparatus mounted on the board for connecting the timing apparatus output alternately to the input of the first counter and the input of the second counter, the switching apparatus including a manual operator effective when operated by the user of the writing board to apply the train of timing pulses alternately to one or the other of the inputs whereby the counters are driven alternately by the timing apparatus.

United States Patent Primary Examiner-Maynard R. Wilbur Assistant Examiner-Joseph M. Thesz, .l r. Atmrney-Prangley, Baird, Clayton, Miller & Vogel ABSTRACT: There is disclosed a portable writing board comprising a flat board having a size and shape to be conveniently supported upon a limb of the user and adapted to receive paper thereon for writing purposes, timing apparatus mounted on the board for producing a train of timing pulses at an output therefor, a first timing pulse counter mounted on the board and including an input and an indicator output, a second timing pulse counter mounted on the board and including an input and an indicator output, and switching apparatus mounted on the board for connecting the timing apparatus output alternately to the input of the first counter and the input of the second counter, the switching apparatus including a manual operator effective when operated by the user of the writing board to apply the train of timing pulses alternately to one or the other of the inputs whereby the counters are driven alternately by the timing apparatus.

PATENTEDFEBJQIQH I I 3562,4953 SHEET-10F 4 v 5()\ IMPULSE IMPULSE 7O COUNTER? coumeraz Inventors CARL S. SPETZLER BY CARL L.DUNBAR PXTENTEU FEB 19 SHEU 2 OF 4 in 01. E

mmon- BATTERY OPERATED TIMING DEVICE The present invention relates to writing boards and more particularly to a writing board which has a plurality of electrically operated digital impulse counters mounted thereon for the timing of events, such writing boards being particularly suitable for use by Industrial Engineers for time study purposes.

Some of the writing boards now being used for time study purposes have three mechanically driven stop watches mounted thereon and include a manual indexing lever which is effective to substantially simultaneously terminate operation of one of the watches so as to enable the user of the writing board to take a reading thereof, to reset a second one of the watches in preparation for a subsequent timing operation, and concurrently to start operation of the third watch to time an occuring event. While such an arrangement is mechanically operative, the quick reading and necessary interpolation required to obtained the elapsed time from the type of stop watch normally employed introduces a certain amount of operator error into the study. I

In addition, the use of three watches may tend to confuse the user of such writing board when the events to be timed transpire very rapidly, thereby introducing further operator error into the study.

Accordingly, it is a primary object of the invention to provide a writing board of a size and shape to be be conveniently supported upon a limb of the user, which board is equipped with a pair of digital, dial-type counters which enable the user of the board to take an immediate and accurate reading of the elapsed time.

In addition to the foregoing operator error which may be introduced into the study when using a board having more than one watch mounted thereon, the use of a plurality of watches also may introduce a certain amount 'of fixed error into the study caused by differences in accuracy among the watches being used.

Accordingly, it is another object of the invention to provide a writing board of the character described which is equipped with a pair of digital type impulse counter switch which are alternately driven by a train of timing pulses generated by a single clock.

It is a further object of the invention to provide, in a writing board of the character described, switching apparatus which is effective alternately to terminate operation of one of the counters so as to enable the user to take areading thereof and concurrently to reset and initiate operation of the second counter for timing a different event.

It is still a further object of the invention to provide a writing board of the character described wherein the timing apparatus is battery operated.

Still a further object of the invention is to provide, in a writing board equipped with the battery operated timing apparatus of the character described, electronic switch means which is operative to prevent the train of timing pulses from being applied to the impulse counters when the battery voltage applied to the circuit is less than a predetermined value.

It is still another object of the invention to provide a timing system comprising a pair of digital impulse counters driven by a single electrically energized clock and including switching apparatus for alternately resetting the counters and concurrently applying a train of timing pulses to the corresponding reset counter; the timing system being adapted for use on a writing board or other surface for the timing of events.

In accordance with one aspect of the invention, there is provided a portable writing board comprising a flat board having a size and shape to be conveniently supported upon a limb of the user and adapted to receive a paper thereon for writing purposes. Timing apparatus is mounted on the board for producing a train of timing pulses at an output therefor. A first timing pulse counter is mounted on the board and includes an input and an indicator output. A second timing pulse counter also is mounted on the board and includes an input and an indicator output. Finally, switching apparatus is mounted on the board for connecting the timing apparatus output alternately to the input of the first counter and the input of the second counter, the switching apparatus including a manual operator effective when operated by the user of the writing board to apply the train of timing pulses alternately to one or the other of the inputs, whereby the counters are driven alternately by the timing apparatus.

Further features of the invention pertain to the particular arrangement of the elements of the writing board, whereby the above outlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification when taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of a writing board embodying the present invention;

FIG. 2 is an enlarged partial view in plan section of the writing board of FIG. 1 with parts thereof broken away, illustrating in greater detail the switching apparatus thereof;

FIG. 3 is an enlarged exploded perspective partial view of the writing board of FIG. 1, illustrating in greater detail the configuration and operation of the switching apparatus forming part of the present invention;

FIG. 4 is an enlarged view in vertical section of the writing board, taken along the line 4-4 in FIG. 1, illustrating in greater detail operation of a portion of the switching apparatus and the circuit means of the timing apparatus;

FIG. 5 is an enlarged view in vertical section of the writing board taken along the line 5-5 in FIG. I, illustrating another portion of the switching apparatus and the clock and circuit means of the timing apparatus;

FIG. 6 is an enlarged plan view illustrating the timing apparatus forming part of the present invention as contained within the lower housing mounted on the writing board; and

FIG. 7 is one form of the electrical circuit of the timing apparatus.

Referring now to the drawings and more particularly to FIG. 1 thereof, there is illustrated a writing'board embodying the present invention and designated generally by the reference numeral 10. The board 10 comprises a relatively flat member which is generally rectangular and has a top surface 11 and a bottom surface 12. The board 10 may be formed from any suitable material which is sufficiently stiff or rigid to provide a proper writing surface for the paper carried thereon and which is light enough to minimize fatigue of the user. For example, the board 10 may be made of plastic, pressed wood fiber, bakelight or wood.

The writing board 10 is normally disposed on the forearm of the user, and, as shown in FIG. 1, the lower left-hand corner of the board 10 has a slightly inwardly curved portion 13 which provides a surface adapted to comfortably rest against the lower portion of the chest of the user. On the side of the board 10 adjacent the curved portion 13 there is provided a curved recess 14, the recess 14 being shaped to comfortably accommodate the upper portion of the users arm which is slightly above his elbow.

The corner of the board diagonally across from the curved portion 13 is concavely curved as at 15 so as to accommodate free movement of the hand of the user. The board is further provided with a generally rectangular opening 16 (FIGS. 4 and 5) to receive the counters and switching apparatus as described in greater detail hereinafter.

The board 10 is provided with an upper housing 20 disposed adjacent to the upper end thereof as view in FIG. I. The upper housing 20 includes a top shell portion 21 having sidewalls 22, an upwardly inclined front portion 23, a rear wall 24 and a flat portion 25 connecting the upper inclined portion 23 to the rear wall 24. As seen in FIGS. 2, 4 and 5, the sidewalls 22, the lower end of the inclined front portion 23 and the rear wall 24 are generally coextensive to the rectangular opening I6 in the board 10.

The upper housing 20 further includes a lower shell 26 positioned below the bottom surface 12 of the board, the lower shell 26 including a bottom wall 27, an upwardly inclined front wall 28 extending from the bottom wall 27 to the bottom surface 12 of the board, an upwardly inclined rear panel 29, and an upstanding rear wall 30 lying in the same plane as the rear wall 24 of the top shell 21.

As best seen in FIGS.4 and 5, the top shell21 and the bottom shell 26 have complementary peripheries and cooperate when fastened to the board 10, to provide a chamber 31 within which is disposed the counters and switching apparatus of the present invention. The top shell 21 and the bottom shell 26 may be fastened to one another and to the board by means of screws (not shown) which are passed through suitable aligned openings 32 (FIG. 2) provided therein. Alternately, the top shell 27 and the board 10 may be integrally formed of a plastic material. A pair of spring clips 33 are fixedly disposed on the top surface 11 of the board for releasably receiving one end of the piece of paper to be positioned on the board.

As shown in FIG. 1, the inclined front wall 23 of the top portion 21 is provided with a manually operable switch 35 secured thereto by way of screws 367 The switch 35 controls operation of the timing apparatus in the manner hereinafter described.-

Also disposed on the inclined wall 23 of the upper housing 20 is a first member for indicating elapsed time, which member, in accordance with the present invention, comprises a digital, dial-type, impulse counter 50. The counter 50 is disposed within the compartment 31 defined by the upper housing 20, and the front face thereof is positioned adjacent to a rectangular opening 51 provided in the wall 23. The counter 50 is fastened to the wall 23 of the housing by four mounting screws 52.

The counter 50 includes four rotatable dials 53 from which the elapsed time of a timed event may be accurately read as illustrated by the numbers 23" thereon. The counter 50 is pro vided with a mechanically operated reset button 55, which, when depressed, is effective to reset the four digital dials of the counter to a zero setting. The counter 50 is provided with a mechanically operated reset button 55, which, when depressed, is effective to reset button 55 the four digital dials of the counter to a zero setting. The reset button 55 is operated by actuating means designated generally as 60, which actuating means are in turn controlled by the switching apparatus designated generally as 100.

As shown in FIGS. 1, 2, and 5, the actuating means 60 comprises an inverted L-shaped member having a vertical leg 61 which extends through a rectangular notch 62 in the inclined front wall 23, and a horizontal leg 63 which extends over the counter 50 where it terminates directly over the reset button 55. As best seen in FIG. 4, the horizontal leg 63is provided with an opening through which a threaded bolt 64 is passed, the bolt 64 being held thereon by a nut 65. The nut 65 and bolt 64 enable the field adjustment of the actuating member 60 which may be necessitated by allowable dimensional variances caused in manufacturing.

A second digital impulse counter 70 is disposed within the compartment 31 and also is mounted on the inclined front wall 23, adjacent to the first counter 50. The second counter 70 is mounted in a rectangular opening 71 in the wall 23 by four mounting screws 72. The second counter 70 is identical to the first counter 50 and includes a reset button 75. There also is provided a second actuating means 80 including a venical legal which passes through a rectangular notch 82 in the wall 23, a horizontal leg 83 and a bolt 84 and nut 85, all of which cooperate with the second counter 70 in the manner heretofore described in connection with the first counter 50.

To complete the general description of the board, it will be seen in FIGS. 1, and 6 that a lower housing 90 is secured to the bottom surface 12 of the board. The lower housing 90 is generally rectangular and includes a pair of sidewalls 91, an upper wall 92, a lower wall 93 and a bottom wall 94. The lower housing 90 is secured to the board by a plurality of I end of theboard, the weight thereof offsets theweight of the, I

screws 95 which are passed through suitable openings in the board 10 and into the openings 96 provided in the upstanding walls of the lower housing. Disposed within the lower housing 90 are the clock and the electrical circuitry for generating the train of timing pulses which is ultimately applied to the impulse counters 50 and 60, all as described in grcaterdetail hereinafter. By disposing the timing apparatus near the lower counters and switching apparatus, thereby to balance the board 10 when it is disposed on the arm of the user.

Finally, as illustrated in dashed lines in FIG. 1, a generally Ushaped channel member 97 extends between the lower housing 90 and the upper housing 20, the channel member 97 providing a shield for the electrical conductors which translate the train of timing pulses to the impulse counters in the upper housing 20.

With reference now. to FIGS. 2 and 3, the switching apparatus 100 for selectively controlling operation of the first and second counters 50 and 70 will now be described in greater detail. The switching apparatus 100 includes a first shaft 101 which is rotatably supported in the top shell 21 of the housing 20. The shaft 101 includes an inner portion 102 which is disposed within the compartment 31 and is rotatably mounted on the sidewall 22 of the shell 21 by a bushing 103, the portion of the shaft 101 extending beyond the shell 21 being bent so as to provide an operator portion 104. As best seen in FIG. 2, the operator portion 104 of the shaft is provided with a knurled surface 105 thereby to facilitate operation thereof.

The inner end 102 of the shaft 101 is hollowed out to provide a tubular chamber 106, the terminal end thereof being provided with a pair of axially extending and diametrically disposed grooves 107. A collar 108 is slidably mounted on the inner end 102 of the shaft for axial movement relative thereto. A pin 110 extends through diametrically arranged openings provided in the collar 108 and is rigidly fixed with respect thereto, the pin 110 having a diameter slightly less than the circumferential extent of each of the grooves 107 in the end portion 102 of the shaft 101, whereby the portion of the pin 110 disposed within the collar 108 is permitted to move laterally within the grooves 107 in the shaft or axially with respect to the shaft 101, while the grooves 107 cooperate with the pin 1 10 so as to cause rotation thereof upon rotation of the shaft 101.

As best seen in FIGS. 2 and 3, a compression spring 111 is disposed within the tubular chamber 106 provided in the shaft 101, the outermost end of the spring 111 abutting against that portion of the pin 110 disposed between the grooves 107 and serving to bias the pin 110 and thereby the collar 108 axially toward the terminal end of the shaft 101.

A second pin 112 is rigidly affixed to the shaft 101 and is disposed normal thereto, the pin 112 serving to receive one end of a return spring 113. The opposite end of the return spring 113 is connected to an anchor pin 114 which is rigidly imbedded in the sidewall 22 of the shell 21. As seen in FIG. 3, the shaft 101 normally is rotated in a counterclockwise direction, the extent of rotation thereof being limited by the engagement of the operator portion 104 thereof with a pair'of outwardly extending stop members 115 imbedded in the adjacent sidewall 22 of the shell 21. When the operator portion 104 is depressed and then released, the shaft 101 returns to the position illustrated due to the action of the return spring 113 on the pin 112 affixed to the shaftv Operation of the first shaft 101 is intended to cause intermittent rotation of a second shaft which is rotatably mounted within the upper shell 21 of the housing 20. The second shaft 120 extends through a pair of bushings 121 and 122 which in turn are rigidly mounted in a pair of generally rectangular and vertically arranged wall members 125 and 127, the wall members being affixed to the respective sidewalls of the counters 50 and 70, It will be understood, however, that in lieu of the wall members 125 and 127, suitable partitions for receiving the second shaft 120 may be molded as part of the upper shell 21 of the housing 20. Each of the wall members 125 and 127 has a generally reverse directed C-shaped member 128 affixed thereto, the upper and lower horizontal flanges of which are provided with aligned openings 129 through which pass the vertical legs 61 and 81 of the associated actuating means 60 and 80.

The second shaft 120 is adapted to be intermittently rotated by way of a ratchet arrangement which cop cooperates with the pin 110 carried by the first shaft 101. The ratchet arrangement includes a circular member 130 which is rigidly secured to the end of the shaft 120 adjacent the inner end 102 of the shaft 101. The circular member 130 is provided with a plurality of axially extending teeth 131 equidistantly spaced about the periphery thereof. Each tooth 131 includes an inclined surface 132 which terminates in an axially extending straight wall portion 133, the straight wall portion 133 terminating as a recessed groove 134 defined by the planar surface 135 of the circular member 130 and the body of the tooth.

Each groove 134 is of a diameter only slightly greater than the diameter of the pin 110 a carried by the shaft 101, whereby the pin 110 is adapted to firmly seat within the groove 135 so that when the shaft 101 is rotated, the pin 110 applies a generally tangentially directed force to the circular member 130, the inclined surface 132 causing the pin 110 to move axially relative to the circular member 130 whenthe shaft 101 is rotated to its normal position by operation of the return spring 113. 1

A switch cam 140 is fixedly mounted to the shaft 120 adjacent the circular member 130. The switch cam 140 includes a plurality of alternately arranged and equiangularly spaced actuating sectors 141 and dwell sectors 142. In a preferred embodiment, the circular member 130 and the switch cam 140 are formed as a single member.

The switch cam 140 is provided for controlling operation of a switch 145, the switch 145 being rigidly affixed to the reverse C-shaped member 128 on the wall 125 disposed adjacent thereto. The switch 145 includes a switch arm 146 which is operative to depress a switch contact 147 disposed therein. The outer end of the switch arm 146 is provided with a follower 148 rotatably mounted within the upstanding legs of a U-shaped support 149 rigidly affixed to the end of the switch arm.

As illustrated, the switch 145 has three terminals designated as 145A, 1458, and 145C; terminal 145A being connected by suitable conductors (not shown) to the timing-apparatus for receiving the train of timing pulses therefrom, terminal 1458 being connected to the counter 50 and terminal 145C being connected to the counter 70. When the switch contact 147 is depressed, an electrical connection is made through terminals 145A and 145B, and when the switch contact 147 is released, an electrical connection is made through terminals 145A and 145C. I

The follower 148 and switch arm 146 cooperate with the switch cam 140 to actuate the switch contact 147. When the follower 148 resides within a dwell sector 142 of the switch cam, the switch arm 146 is allowed torise and thereby release the switch contact 147, thereby to break the electrical connection between the timing apparatus and the first counter 50 and establish an electrical connection between the timing apparatus and the second counter 70. Conversely, when the switch follower 148 contacts an actuating sector 141, the switch arm 146 is depressed to close the switch contact 147 and thereby energizes the first counter .50 and breaks the cir cuit to the second counter 70. Because the actuating sectors and dwell sectors are alternately arranged, it is clear that the counters 50 and 70 will be alternately operated by rotation of the switch cam.

A first reset cam 150 is rigidly affixed to the shaft 120 adjacent to the wall 125. The first reset cam 150 includes a plurality of alternately arranged and equiangularly spaced actuating sectors 151 and dwell sectors'152.

The reset cam 150 controls and effects reciprocal operation of theactuating means 60 for the first counter 50 by way of a link 153 which is pivotally secured at 154 to the wall 125 and which includes a pin follower 155 rigidly secured to the end thereof adjacent the reset cam 150 for cooperation therewith. A pivot pin 156 pivotally connects the opposite end of the link 153 to the vertical leg 61 of the actuating means 60, thereby to effect reciprocal movement of the actuating means when the pin follower 155 rides over an actuating sector 151 of the reset cam 150 upon rotation of the shaft 120.

As best seen in FIGS. 2 and 3, the bolt 64 carried by the horizontal leg of the actuating means 60 is adjusted so that it normally abuts the top surface of the reset button 55 when the pin follower 155 is disposed in a dwell sector of the reset cam 150.

A second reset cam 170 is rigidly affixed to the shaft 120 adjacent to the wall 127, the second reset cam 170 being identical to the first reset cam 150 ad and including the plurality of alternately arranged and equiangularly spaced actuating sectors 171 and dwell sectors 71 172, the peak points of the actuating sectors 171 of the second reset cam 170 being 180 out of phase with respect to the peak points of the actuating sectors 151 of the first reset cam 150. I

The reset cam 170 controls and effects reciprocal operation of the actuating means for the second counter 70 by way of a link 173 which is pivotally secured at 174 to the wall 127 and which includes the pin follower 175 rigidly secured to the end thereof adjacent the reset cam 170 for cooperation therewith. A pivot pin 176 pivotally connects the opposite end of the link 173 to the vertical leg 81 of the actuating means 80, thereby to effect reciprocal movement of the actuating means when the follower pin 175 rides over an actuating sector 171 of the reset cam 170 as the shaft rotates.

As best seen in FIGS. 2 and 3, the bolt 84 is carried by the horizontal leg of the actuating means 80 is adjusted so that it normally abuts the top surface of the reset button 75 when the pin follower 175 is disposed in a dwell sector of the reset cam 170.

1n the embodiment illustrated, the circular member is provided with 10 equiangularly spaced teeth 131, whereby each tooth subtends an arc of substantially about 36; similarly, the switch cam an and each of the first ad the switch cam 140 and each of the first and second reset cams and are provided with five equiangular actuating sectors and five equiangular dwell sectors, each of which subtends an arc of substantially about 36.

As illustrated in FIGS. 2 and 3, the peak points of the actuating sectors 171 of the second reset cam 170 are disposed 180 ut of phase with respect to the peak points of the actuating sectors 151 of the first reset cam 150 whereas the actuating sectors 171 of the reset cam 170 are substantially in phase with respect to the actuating sectors 141 of the switch cam 15 140 whereby depression of the switch contact 147 to operate the second counter 70 occurs substantially concurrently with the resetting of the second counter to a zero setting. However, the cams 140, 150 and 170 may be provided with different configurations so long as operation of the cams retains the 180 phasing in terms of actuation of the switch and reset buttons. In this regard, the 180 phase represents an operating condition as opposed to an actual angular measurement.

The switch 145 is aflixed to the member 128 in a position such that the switch follower 148 is normally disposed at the beginning of either an actuating sector 141 or a dwell sector 142, depending upon the position of the switch cam 140; whereas each of the pin followers 155 and are positioned on the respective links 153 and 173 so that they normally reside substantially along on one of the lines of the intersection between the actuating sectors and the dwell sectors, as shown in FIG. 3.

As heretofore noted, rotational movement of the operator portion 104 of the shaft 101 is limited by the two stop members 115 on the housing, the extent of angular movement of the shaft 101 being limited thereby to approximately 36. Because there are ten equiangularly spaced teeth 131 on the circular member 130, it will be appreciated that each na manipulation of the operator portion 104 by the user of the board will cause one end of the pin 110 to engage the adjacent groove 134 of one of the teeth 131 on the circular member and thereby cause the second shaft 120 to rotate through an arc of substantially about 36. Likewise, because there are a total of ten equal sectors on the switch cam 140 and each of the reset cams 150 and 170, with each of these sectors having an angular extend extent of 36, each manipulation of the operator portion 104 by user causes each of the cams 140, and 150 and 170 to rotate 36, thereby defining a full cycle for each sector thereof. For each 36 cle of rotation of the shaft 120,'the switch follower 148 will be disposed at a point at the beginning of either a dwell sector and or an actuating sector on the switch cam 140, while one of the pin followers 155 or 175 will be disposed immediately adjacent either the trailing edge of one of the actuating sectors, as shown by the pin follower 155, or will be disposed adjacent the leading edge of the next actuating sector, as shown by the pin follower 175. From the foregoing, it will be apparent that each time the shaft 120 is rotated in response to manipulation of shaft 101, one of the counters is reset and immediately starts counting while the other counter maintains the elapsed reading thereon because the follower pin for the reset actuating means has rotated through and is disposed in a dwell sector.

The timing apparatus forming part of the invention for generating the train of timing pulses-applied to the counters will now be described with particular reference to FIGS. 6 and 7, As heretofore stated, the lower housing 90 carries within it a clock and the electrical circuitry forming part of the timing apparatus. As seen in FIG. 6, there is disposed within the lower housing 90 an electrically energized clock 200 which may be of the type sold under the trade name of Westclox, known as their no-cord movement." A battery is mounted within the housing 90 adjacent to the clock 200 and serves as the energy source therefor, as described hereinafter. A circuit board 202 is mounted within the housing adjacent to the clock 200 by a plurality of screws 203 (FIG. 4). Mounted on the circuit board 202 are the various electrical components which provide a frequency dividing circuit as subsequently described. At the far left-hand side of the housing there is disposed a pair of batteries 204 which provide the energy source for the frequency dividing circuit and serve to energize the counters 50 and 70.

Referring now to FIG. 7 of the drawings, there is shown a preferred form of electrical circuit employed in the invention and including the electrically energized clock 200 with one of the terminals thereof being coupled through a manually operated switch 205 to the negative terminal of the battery 201, the positive terminal of the battery being coupled through a resistor 206 to the other terminal of the clock 200. Closure of the switch 205 permits the battery 201 to pass a DC current through the resistor 206 and into the clock 200 thereby causing the clock200 to generate a train of timing pulses at a frequency on the order 200 pulses per minute, which pulses are to be reduced in frequency by a frequency dividing circuit indicated generally by the numeral 210.

Electrical energy for the frequency dividing circuit 210 is provided by the batteries 204, the positive terminal thereof being coupled through the manually operable switch 35 which switch is in turn coupled through a resistor 212 and a Zener diode 213 back to the negative terminal of the battery 201, whereby closure of the switch 35 produces a negative DC supply-voltage on the conductor 214 with respect to the conductor 2l5, the Zenerdiode 213 maintaining the negative DC supply voltage on the'conductor 214 at a constant predetermined value. A

The frequency dividing circuit 210 includes a PNP amplifier transistor 220 having the emitter thereof coupled through a load resistor 221 to the conductor 214. The negative DC supplyvoltage 'on cod conductor 214 is coupled to a resistor 222which in turn is coupled to the base of transistor 220 to amplify pulse pulses applied thereto. The train of timing pulses from the clock 200-is coupled through capacitor 223 to the base of the amplifier transistor 220, which transistor provides an amplified train of timing pulses on the collector thereof. The amplified pulses are thence coupled through a resistor 224 to an emitter coupled monostable multivibrator circuit 230.

The multivibrator circuit 230 includes a pair of PNP transistors 231 and 232 having the emitters thereof coupled together and through a common emitter resistor 233 to conductor 215, the collectors of the transistors 231 and 232 being respectively coupled through load resistors 234 and 235 to conductor 214. A pair of biasing s resistors 234 and 235 to conductor 214. A pair of biasing resistors 236 and 237 are coupled in series between conductors 214 and 215 with the junction thereof being coupled to the base of the transistor 231 to provide a quiescent bias transistor thereof therefore. The base of transistor 232 is coupled through a resistor 238 and a frequency determining potentiometer 239 to conductor 215, to provide a quiescent bias for transistor 232. A frequency determining capacitor 240 is coupled between the collector of transistor 231 and the base of transistor 232.

The multivibrator circuit 230 operates to reduce the frequency of the timing pulses according to the values of potentiometer 239 and 'a capacitor 240 and preferably these values are selected such that the frequency of the pulses at the collector of the transistor 232' is one third the frequency of pulses provided by amplifier transistor 220, and assuming the clock 200 generates pulses at a frequency of 300 pulses per minute, a train of pulses at a frequency of pulses per minute will be developed on the collector of transistor 232.

The collector of transistor 232 is coupled through a capacitor 245 to the base of a PNP amplifier. transistor 246, the emitter of which is coupled through a resistor 247 to conductor 215 and the collector of which is coupled through a load resistor 248 to conductor 214. A biasing resistor 249 is coupled from the base of transistor 246 to conductor 215, whereby transistor 246 is operative to amplify the train of pulses developed on the collector of transistor 232. The amplified and divided pulses are coupled through a capacitor 250 to the base of an NPN switching transistor 251, the collector of which is coupled through a resistor 252 to one terminal of the manually operable switch 35, and the emitter of which is coupled to the negative terminal of the battery 204.

When the switch 35 is in the closed positionand when the transistor 251 is rendered heavily conductive so that a very low impedance exists between its collector and its emitter, the entire voltage from the a battery 204 will appear across the resistor 252. When the transistor 251 is rendered nonconductive, the voltage across the resistor 252 will be zero. The duration that the transistor 251 is conductive is determined by the duration of the timing pulses applied thereto and the frequency at which transistor 251 becomes conductive is determined by the frequency of the timing pulses, whereby a train of pulses is caused to appear across the resistor 252 between the output terminals 254 and 255, the pulses having a frequency equal to the frequency of the timing pulses generated by the multivibrator circuit 230 and having a peak-to-peak amplitude approximately equal to the value of the voltage from the battery 204. A diode 253 is coupled in shunt with resistor 252 to.

protect the transistors in the dividing circuit 210 from inductive oscillation created in the impulse counters 50 and 70.

A suitable conductor (not shown) connects the'terminal 255 to the terminal A of the switch 145, the conductor being disposed within the channel member 97, while another conductor connects terminal 254 to the opposite terminals of the counters.

In a preferred form ,of the invention, the various components of the timing apparatus have the following values:

Battery 201 1.5 volts Battery 204 12.7 volts Resistor 206 47 ohms Resistor 212 150 ohms Resistor 221 15,000 ohms Resistor 222 470,000 ohms Capacitor 223 2 microfarads Resistor 224 82,000 ohms Resistor 233 5,100 ohms Resistor 234 22,000 ohms Resistor 235 10,000 ohms Resistor 236 I 100,000 ohms Resistor 237 33,000 ohms Resistor 238 680,000 ohms Potentiometer 239 500,000 ohms Capacitor 240 l microfarad Capacitor 245 l microfarad Resistor 247 100 ohms Resistor 248 6,800 ohms Resistor 249 1 47,000 ohms Capacitor 250 7 I microfarads Resistor 252 100 ohms In addition, the counters 50 and 70 are of the type sold under the trade name Sodecd' as model number TCE-BZ4E.

In the preferred form of the invention the clock 200 will provide a train of timing pulses having a frequency of 300 pulses per minute and the multivibrator circuit 230 will reduce the frequency to I00 pulses per minute to provide, at the output terminals 254 and 255, a train of timing pulses having a frequency of I00 pulses per minute.

In operation, so long as the switch 35 is open, no pulses are transmitted to either of the counters 50 or 70 through the switch 145. When the switch 35 is closed, the train of timing pulses will, so long as the batteries 204 generate a minimum voltage, be applied to one of the counters to cause operation thereof at the same frequency as the pulses applied thereto.

At the start of a normal operation, the switching apparatus 100 may assume the position shown by the full lines in FIGS. 2, 3 and 5, wherein the switch follower 148 is disposed at the beginning of an actuating sector 141 of the switch cam 140, the pin follower 155 of the associated counter 50 is do disposed immediately adjacent to the trailing edge of an actuating sector of the reset cam 150, and the pin follower 175 is disposed adjacent to the leading edge of the next actuating sector of the reset cam 175.

To begin operation, the user must first close the switch 205 for the clock 200, whereupon the clock begins to generate the train of timing pulses. The switching apparatus 100 may assume the position shown by the full lines in FIGS. 2,3 and 5, wherein the switch follower 148 is disposed at the beginning of an actuating sector 141 of the switch cam 140. The pin follower 155 of the associated counter 50 is disposed immediately adjacent to the trailing edge of an actuating sector of the reset cam 150, and the pin follower 175 is disposed adjacent to the leading edge of the next actuating sector of the reset cam 175.

To begin operation, the user must first close the switch 205 for the clock 200, whereupon the clock begins to generate the train of timing pulses. The switch 35 is then closed, and because the switch follower 147 happens to be depressed, the first counter 50 immediately starts to count. However, because closure of the switch 35 completes a circuit to the counter 50, the first pulse received by the counter is not representative of the normal frequency of operation. For this reason, the user, at the start of the first event to be timed, must depress the operator portion 104 of the switching apparatus so as to cause the second counter to time the event.

Rotation of the operator portion 104 causes one end of the pin to engage an adjacent groove 134 of one of the teeth 131 so as to cause the circular member and the shaft 120 to rotate through a predetermined are arc, which in the embodiment shown, is about 3620 Upon rotation of the shaft 120, the switch cam rotates 36, whereby the switch follower 148 moves from the beginning of the actuating sector 141 thereof to the beginning of the adjacent dwell sector I42, thereby breaking the electrical connection between the terminal 255 and the terminal B, stopping operation of the counter 50 and simultaneously establishing an electrical connection between the terminal 255 and the terminal 145C, whereby the train of timing pulses at the output terminal 255 is applied to the second counter 8 70 which immediately begins to count. Concurrently, therewith, the pin follower of the counter 50 is rotating through a dwell sector of the reset cam 50, whereby termination of operation of the counter 50 is as accomplished in a manner which maintains the position of the dials on the indicator output thereof so that a reading can be taken.

Rotation of the shaft 120 also causes concurrent rotation of the second reset cam so that the pin follower associated therewith passes through an adjacent actuating sector, thereby causing the link 173 to rotate counterclockwise, as illustrated by the dashed lines in FIG. 5, and thereby causing the vertical leg portion 83 of the actuating means 80 to move downwardly so that the bolt 84 forcefully engages the reset button 75 to effect depression thereof and the resetting of the four dials of the counter 70 to a zero setting.

As previously explained, each actuating sector 171 subtends an are substantially equal to the extent of angular rotation of the shaft 101, whereby the pin follower 175 returns to a position adjacent to the trailing edge of the actuating sector, as illustrated by the pin follower 155. Each of the reset buttons 55 and 75 is spring actuated in the counter so that after depression thereof each of the reset buttons immediately returns to the position shown in FIG. 4. The return movement of each of the reset buttons raises the horizontal leg of the associated actuating means and thereby causes the associated pin follower to be disposed in contact with the dwell sector of the respective reset cam.

When the user of the board releases the operator portion 104, the shaft 101 returns to its normal position by the action of the return spring 113 on the pin 112, all as previously described. As the shaft 101 rotates in the clockwise direction to return to is its normal position, the ends of the pin 110 rotate over the inclined walls 132 of the ratchet teeth 131 which cause the pin to move laterally in the grooves 107 in the tubular portion of the shaft 101. The grooves 107 permit movement of the pin 110 axially with respect to the circular member 130 until the ends of the pin 1 10 ride over the edges of the inclined surfaces 132 of the teeth, whereupon the compression spring 111 causes the pin 110 to return to a position of abutment against the face 135 of the circular member 130.

Upon a second manipulation of the operator 104 by the user, one end of the pin 110 will again engage a groove 134 of the adjacent ratchet tooth 131 thereby to cause rotation of the circular member 130 ad and the second shaft 120 through a second predetermined cycle, whereupon the switch cam 140 rotates so that one of the actuating sectors 141 thereof depresses the follower member 148 as shown in FIG. 3, thereby terminating operation of the second counter 70 and electrically connecting the first counter 50 to the output of the timing apparatus. At substantially the same time, the reset "cam 150 for the first counter 50 will have rotated through an actuating sector 151 to reset the first counter 50 to zero setting, whereupon the first counter begins to count from zero and is a capable of indicating elapsed periods of time a at a frequency of 100 counts per minute. The second reset cam 170 during this period rotates through a dwell sector 172, the electrical circuit thereto having been broken by action of the switch cam 140, whereby the user of the board can now take a reading from the deenergized counter while the second counter is operating. At this time, each of the cams 140, 150 and 170 and the followers 148, 155 and 175 will once again be in the star start position shown in FIG. 3 in preparation for the next operation.

lt is apparent from the foregoing that each time the switching apparatus'l00 is operated by the user of the board, the switch. 145 is operated so as to effect alternate operation of. the counters 50 and 70 and the concurrent alternate resetting of the counter which is electrically connected to the output of the timing apparatus; the counters being reset upon alternate operations of the operator 104 whereby each manipulationof the operator causes the follower of one of the or unters to pass through a dwell sector to permit reading of the elapsed time on the dials thereof.

It will also be apparent that the timing apparatus and switching apparatus may be disposed in a single housing for use as a portable timing device without the writingboard in which case the housing would be provided with a planar bottom surface so that it could be placed on a desk or table of or the like. i

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

We claim;

1. A portable writing board comprising a flat board having a size and shape to be conveniently supported a limb of the user and adapted to receive paper thereon for writing purposes, tinting apparatus mounted on said board for producing a train of timing pulses having a first predetermined frequency at an output therefor, frequency dividing means mounted on said board and having an input connected to the output of said timing apparatus for reducing the frequency of said timing pulses to a second predetermined frequency at an output therefore, a first timing pulse counter mounted on said board and includ ing an inputand an indicator output, said first counter being operative in response to application of said train of timing pulses at said second predetermined frequency to the input thereof for indicating elapsed periods of time corresponding to said second predetermined frequency, a second timing pulse counter mounted on said board and including an input and an indicator output, said se second counter including an input and an indicator output, said second counter being operative in response to application to said train of timing pulses at said second predetermined frequency to the input thereof for indicating elapsed periods of time corresponding to said second predetermined frequency, said first counter including amechanically operable reset button effective when including a mechanically operable reset button effective when operated to resetthe indict indicator output thereof to a zero setting, said second cu counter including a mechanically operable reset button efi'ective when operated to reset the indicator output thereof to a zero setting, switching apparatus mounted on said board for connecting said frequency dividing means output alternately to the input of said first counter and the input of said second counter, said switching apparatus including'a shaftrotatably mounted on said board, a manual operator mountedionsaid board for effecting intermittent rotation of said shaft through a predetermined are, a first cam mounted on said shaft for rotation therewith and including alternate actuating sectors and dwell sectors thereon, each of a said actuating sectors and dwell sectors defining a cycle of operation equivalent to the angular extent of rotation of said shaft caused by said operator, first actuating means mounted on said board for operating said first reset button so as to cause said first counter to be reset to the zero setting thereof, said first actuating means including a follower operable in response to rotation of said first cam whereby said first counter is reset only upon alternate manipulations of said operator, a second cam' mounted on said shaft for rotation therewith and'including alternate actuating sectors and dwell sectors thereon, each of said actuating sectors and dwell sectors defining a cycle'of operation equivalent to the angular extent of rotation of said shaft caused by said operator, second actuating means mounted on said board for operating said second reset button so as to cause said second counter to be reset to the zero setting thereof, saidsecond actuating means including a follower operablein response to rotation of said second cam whereby said second counter is reset only upon alternate manipulations of said operator, the actuating sectors of said first and second cams being 180 out of phase with one another whereby successive manipulation of said manual operator effects alternate resetting of said first and second counters, a third cam mounted on said shaft for rotation therewith an including alternate actuating sectors and dwell sectors, each ofsaid actuating sectors and dwell sectors, defining a cycle of operation equivalent to the angular extent of rotation of saidshaft, and'a switch mounted on said board and connected to the output and a switch mounted on said board and connected to the output of said frequency dividing means; said switch being alternately operable in response'to rotation ofsaid third cam-between a first position wherein saidswitch applies said train of timingpulses to said first counter and a second position wherein said switch applies said train of timing pulses to said second counter, the actuating sectors of said first cam and said third cam being substantially in phase with one another so that operation of said shaft concurrently causes saidfirst counter to be reset and said switch to operate to the first position thereof so as to cause said train timing pulses to be applied to said first counter and upon a subsequent operation of a said manual operator said third cam causes said switch to operate to the second position thereof wherein'said train of timingpulses is applied to said second counter and concurrently said secondcam causes said second actuating means to operate so as to reset said second counter, whereby the user of the writing board may take a reading of the elapseda reading of elapsed time from the indicator output of said second counter.

2. The writing board set forth in claim 1, wherein said timing apparatus is electrically energized.

3. The writing board set forth in claim whereinsaid tim-" ing apparatus is battery operated.

4. The writing board set forth in claim 1, wherein each of said pulse counters comprises an impulse counter having digital display dials from which the user of the writing'board can take a direct reading of the'elapsed time measured thereby.

5. A The writing board set forth in claim 4, wherein said frequency dividing means is operative to apply a train of timing pulses of substantially about pulses per minute to said impulse counters.

6. The writing board set forth in claim 1, wherein said timing apparatus comprises an electrically energized clock for producing a train of timing pulses havinga first predetennined frequency at an output thereof therefor, and said frequency dividing means comprises circuit means coupled to said clock and responsive to the train of timing pulses to reduce the frequency thereof to provide said train of timing pulses having the second predetermined frequency at an output therefor; said switching apparatus alternately coupling said frequency dividing circuit means to said pulse counters for translating said train of timing pulses to one of said pulse counters whereby the indicator output of said counter operates at said second predetermined frequency.

7. The writing board set forth in claim 6, wherein said train of timing pulses generated by said clock has a frequency of substantially about 300 pulses per minute and said frequency dividing circuit means reduces the frequency thereof to substantially about 100 pulses per minute.

8. The writing board set forth in claim 6, and further comprising manually operable switch means for selectively controlling operation of said frequency dividing circuit means.

9. The writing board set forth in claim 6, wherein said impulsed counters are disposed substantially adjacent to one end of said writing board and said clock' and a said frequency dividing circuit means are disposedsubstantially adjacent to the opposite end of said writing board so as to approximately equally distribute the weight thereof on said board, thereby to balance said board when it is held in a limb of the associated user.

10. A timing device for use in the timing of events comprising a housing, timing apparatus. carried in said housing for produced producing a train of timing pulses having a first predetermined frequency at an output therefor, frequency dividing means carried in said housing and having an input connected to the outputof said timing apparatus for reducing the frequency of said timing pulses to a second predetermined frequency at an output therefor, a first timing pulse counter mounted on said housing and including an input and an indicator output, said first counter being operative in response to application of said train of timing pulses'at said second predetermined frequency to the input thereof for indicating elapsed periods of time corresponding to said second predetermined frequency, a second timing pulse counter mounted on said housing and including an input and an indicator output, said second counter being operative in response to application of Said train of timing pulses at said second predetermined frequency to the input thereof for indicating elapsed periods of time corresponding to said second predetennined frequency, said first counter includinga mechanically operable reset button effective when operated to reset the indicator output thereof to a zero setting, said 1 second counter including a mechanically operable reset button effective when operated to reset the indicator output thereof to a zero setting, switching apparatus carried in said housing for connecting said frequency dividing means-output alternately to the input of said first counter and the input of said second counter, said switching apparatus including a shaftrotatably mounted on said housing, a manual operator mounted on said housing for effecting intermittent rotation of said shaft through a predetermined are, a first cam mounted on said shaft for rotation therewith and includingaltemate actuating sectors and dwell sectors thereon, each of said actuating sectors and dwell sectors defining a cycle of operation equivalent to the angular extent of rotation of said shaft caused by said operator, first actuating means carried in Saidhousing for operating said first reset button so as to cause said first counter to be reset to the zero setting thereof, said first actuating means including a follower operable in response to rotation of said first cam whereby said first counter is reset only upon alternate manipulations of said operator, at second cam mounted on said shaft for rotation therewith and including alternate actuating sectors and dwell sectors thereon, each of said actuating sectors and dwell sectors defining a cycle of operation equivalent to the angular extend of rotation of said shaft caused by said operator, second actuating means carried in said housing for operating said second reset button so as cause said second counter to be reset to the zero'setting thereof, said second actuatrng means including a follower operable in response to rotation of said second cam whereby said second counter is reset only upon alternate manipulations of said operator, the actuating sectors of said first and second cams being l out of phase with one another whereby successive manipulation of said manual operator effects alternate resetting of said first and second counters, a third cam mounted on said shaft for rotation therewith and including alternate actuating sectors and dwell sectors, each of said actuating sectors and dwell sectors defining a cycle of operation equivalent to the angular extend of rotation of said shaft, and a switch carried in said housing and connected to the output of said frequency dividing means, said switch being alternately'operable in response to rotation of said third cam between a-first position wherein said switch applies said train timing pulses to said first counter and a second position wherein said switch applies said train of timing pulses to said second counter, the actuating sectors of said first cam and said third cam being substantially in phase with one another so that operation of said shaft concurrently causes said first counter to be reset and said switch to operate to the first position thereof so as to cause said train of timing pulses to be applied to said first counter and upon a subsequent operation of said manual operator said third cam causes said switch to operate to the second position thereof wherein said train of timing pulses is applied to said second counter and concurrently said second cam causes a said second actuating means to operate so as to reset said second counter, whereby the user of the timing system may take a reading of the elapsed time from the indicator output of the first counter while the second counter is operated and whereby successive manipulation of said operator causes said first counter to be reset and said switch to move to said first position thereof to effect operation of said first counter while said second cam rotates through a dwell portion thereof so as to the user to take a reading of elapsed time from the indicator output of said second counter.

ll. A portable writing board comprising a fiat board having a size and shape to be conveniently supported upon a limb of the user and adapted to receive paper thereon for writing purposes, timing apparatus comprising a battery operated electrically energized clock mounted on said board for producing a train of timing pulses at an output thereof, a first timing pulse counter mounted on said board and including an input and an indicator output, a second timing pulse counter mounted on said board and including an input and an indicator output, frequency dividing circuit means including electronic switch means operative to prevent application of said train of timing pulses to either of said impulse counters when the battery voltage applied to said circuit is less than a predetermined value coupled to said clock and responsive to the train of timing pulses to reduce the frequency of said train of timing pulses to a second predetermined frequency at an output therefor, and switching apparatus mounted on said board for connecting said timing apparatus output alternately to the input of said first counter and the input of said second counter, said switching apparatus alternately coupling said frequency dividing circuit means to one of said pulse counters for translating said train of timing pulses thereto whereby the indicator output of said counter operates at said second predetennined frequency, said switching apparatus including a manual operator effective when operated by the user of the writing board to apply the train of timing pulses alternately to one or the other of the inputs, whereby said counters are driven alternately by said timing apparatus.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,562 ,499 February 9 Carl S. Spetzler et al.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1 line 26 cancel "be", second occurrence; line 4 counter should read counters same line 40, cancel switch" Column 2 line 68 "View" should read viewed Column 3, line 40, cancel beginning with "the" to line 43 and ending with "setting". Column 5, line 8, cancel "cop"; line 21 cancel "a". Column 6, line 33, cancel "is"; line 41, cancel a same line 41, cancel "ad the switch cam 140 and each of the first; line 48 "180" should read 180 same line 48 "ut" should read out line 52 cancel "l5" line 67 ca "011; line 75, cancel "na". Column 7, line 11, "36 cle" should read 36 cycle line 56 "200" should read 300 1i after "coupled" insert to the conductor 215 and the collect thereof coupled line 72, cancel "cod"; line 73, after "to" second occurrence, insert cause a biasing current to flow through the emitter-base junction of transistor 220, thereby enabling the transistor 220 to line 74, cancel "pulse". Co 8, line 12, cancel "5"; line 16, cancel "thereof". Column 9, 1 61 cancel "do"; line 67 beginning with "To" cancel through 1 7S Column 10, lines 1 and 2 should be canceled; line 18 canc "are"; line 19, "3620" should read 36 line 28, cancel "8: line 32, cancel "as"; line 61, cancel "is"; line 73, canc "ad. Column ll, line 8, cancel "a", first occurrence and seco occurrence; line 33, cancel "of"; line 43, after "supported" insert upon line 50 "therefore" should read therefo lines 58 and 59, cancel beginning with "said" and ending with output"; line 61 "to", second occurrence should read of line 66, cancel the entire line; line 67 cancel "indict"; lin cancel "cu"; Column 12 line 3 cancel "a" line 28 "an" shou read and 7 lines 32 and 33, cancel beginning with "and" a ending with "output"; line 44 cancel "a"; line 75 cancel "thereof". Column 13, lines 18 and 19 "impulsed should read impulse line 20, cancel "a"; line 28 cancel "produced"; line 56 r "are" should read arc Column 14 line 15 "ten should read tent line 19 after "train" insert of line 30, cancel "a"; line 39 after "to", first occurrence insert H enable 5 line 46 "thereof" should read therefor Signed and sealed this 6th day of July 1971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER Attesting Officer Commissioner of Pat 

1. A portable writing board comprising a flat board having a size and shape to be conveniently supported a limb of the user and adapted to receive paper thereon for writing purposes, timing apparatus mounted on said board for producing a train of timing pulses having a first predetermined frequency at an output therefor, frequency dividing means mounted on said board and having an input connected to the output of said timing apparatus for reducing the frequency of said timing pulses to a second predetermined frequency at an output therefore, a first timing pulse counter mounted on said board and including an input and an indicator output, said first counter being operative in response to application of said train of timing pulses at said second predetermined frequency to the input thereof for indicating elapsed periods of time corresponding to said second predetermined frequency, a second timing pulse counter mounted on said board and including an input and an indicator output, said se second counter including an input and an indicator output, said second counter being operative in response to application to said train of timing pulses at said second predetermined frequency to the input thereof for indicating elapsed periods of time corresponding to said second predetermined frequency, said first counter including a mechanically operable reset button effective when including a mechanically operable reset button effective when operated to reset the indict indicator output thereof to a zero setting, said second cu counter including a mechanically operable reset button effective when operated to reset the indicator output thereof to a zero setting, switching apparatus mounted on said board for connecting said frequency dividing means output alternately to the input of said first counter and the input of said second counter, said switching apparatus including a shaft rotatably mounted on said board, a manual operator mounted on said board for effecting intermittent rotation of said shaft through a predetermined arc, a first cam mounted on said shaft for rotation therewith and including alternate actuating sectors and dwell sectors thereon, each of a said actuating sectors and dwell sectors defining a cycle of operation equivalent to the angular extent of rotation of said shaft caused by said operator, first actuating means mounted on said board for operating said first reset button so as to cause said first counter to be reset to the zero setting thereof, said first actuating means including a follower operable in response to rotation of said first cam whereby said first counter is reset only upon alternate manipulations of said operator, a second cam mounted on said shaft for rotation therewith and including alternate actuating sectors and dwell sectors thereon, each of said actuating sectors and dwell sectors defining a cycle of operation equivalent to the angular extent of rotation of said shaft caused by said operator, second actuating means mounted on said board for operating said second reset button so as to cause said second counter to be reset to the zero setting thereof, said second actuating means including a follower operable in response to rotation of said second cam whereby said second counter is reset only upon alternate manipulations of said operator, the actuating sectors of said first and second cams being 180* out of phase with one another whereby successive manipulation of said manual operator effects alternate resetting of said first and second counters, a third cam mounted on said shaft for rotation therewith an including alTernate actuating sectors and dwell sectors, each of said actuating sectors and dwell sectors, defining a cycle of operation equivalent to the angular extent of rotation of said shaft, and a switch mounted on said board and connected to the output and a switch mounted on said board and connected to the output of said frequency dividing means, said switch being alternately operable in response to rotation of said third cam between a first position wherein said switch applies said train of timing pulses to said first counter and a second position wherein said switch applies said train of timing pulses to said second counter, the actuating sectors of said first cam and said third cam being substantially in phase with one another so that operation of said shaft concurrently causes said first counter to be reset and said switch to operate to the first position thereof so as to cause said train timing pulses to be applied to said first counter and upon a subsequent operation of a said manual operator said third cam causes said switch to operate to the second position thereof wherein said train of timing pulses is applied to said second counter and concurrently said second cam causes said second actuating means to operate so as to reset said second counter, whereby the user of the writing board may take a reading of the elapsed time from the indicator output of the first counter while the second counter is operating and whereby successive manipulation of said operator causes said first counter to be reset and said switch to move to said first position thereof to effect operation of said first counter while said second cam rotates through a dwell portion thereof so as to enable the user to take a reading of elapsed time from the indicator output of said second counter.
 2. The writing board set forth in claim 1, wherein said timing apparatus is electrically energized.
 3. The writing board set forth in claim 1, wherein said timing apparatus is battery operated.
 4. The writing board set forth in claim 1, wherein each of said pulse counters comprises an impulse counter having digital display dials from which the user of the writing board can take a direct reading of the elapsed time measured thereby.
 5. A The writing board set forth in claim 4, wherein said frequency dividing means is operative to apply a train of timing pulses of substantially about 100 pulses per minute to said impulse counters.
 6. The writing board set forth in claim 1, wherein said timing apparatus comprises an electrically energized clock for producing a train of timing pulses having a first predetermined frequency at an output thereof therefor, and said frequency dividing means comprises circuit means coupled to said clock and responsive to the train of timing pulses to reduce the frequency thereof to provide said train of timing pulses having the second predetermined frequency at an output therefor, said switching apparatus alternately coupling said frequency dividing circuit means to said pulse counters for translating said train of timing pulses to one of said pulse counters whereby the indicator output of said counter operates at said second predetermined frequency.
 7. The writing board set forth in claim 6, wherein said train of timing pulses generated by said clock has a frequency of substantially about 300 pulses per minute and said frequency dividing circuit means reduces the frequency thereof to substantially about 100 pulses per minute.
 8. The writing board set forth in claim 6, and further comprising manually operable switch means for selectively controlling operation of said frequency dividing circuit means.
 9. The writing board set forth in claim 6, wherein said impulsed counters are disposed substantially adjacent to one end of said writing board and said clock and a said frequency dividing circuit means are disposed substantially adjacent to the opposite end of said writing board so as to approximately equally distribute the weight thereof on said board, theReby to balance said board when it is held in a limb of the associated user.
 10. A timing device for use in the timing of events comprising a housing, timing apparatus carried in said housing for produced producing a train of timing pulses having a first predetermined frequency at an output therefor, frequency dividing means carried in said housing and having an input connected to the output of said timing apparatus for reducing the frequency of said timing pulses to a second predetermined frequency at an output therefor, a first timing pulse counter mounted on said housing and including an input and an indicator output, said first counter being operative in response to application of said train of timing pulses at said second predetermined frequency to the input thereof for indicating elapsed periods of time corresponding to said second predetermined frequency, a second timing pulse counter mounted on said housing and including an input and an indicator output, said second counter being operative in response to application of said train of timing pulses at said second predetermined frequency to the input thereof for indicating elapsed periods of time corresponding to said second predetermined frequency, said first counter including a mechanically operable reset button effective when operated to reset the indicator output thereof to a zero setting, said second counter including a mechanically operable reset button effective when operated to reset the indicator output thereof to a zero setting, switching apparatus carried in said housing for connecting said frequency dividing means output alternately to the input of said first counter and the input of said second counter, said switching apparatus including a shaft rotatably mounted on said housing, a manual operator mounted on said housing for effecting intermittent rotation of said shaft through a predetermined are, a first cam mounted on said shaft for rotation therewith and including alternate actuating sectors and dwell sectors thereon, each of said actuating sectors and dwell sectors defining a cycle of operation equivalent to the angular extent of rotation of said shaft caused by said operator, first actuating means carried in said housing for operating said first reset button so as to cause said first counter to be reset to the zero setting thereof, said first actuating means including a follower operable in response to rotation of said first cam whereby said first counter is reset only upon alternate manipulations of said operator, a second cam mounted on said shaft for rotation therewith and including alternate actuating sectors and dwell sectors thereon, each of said actuating sectors and dwell sectors defining a cycle of operation equivalent to the angular extend of rotation of said shaft caused by said operator, second actuating means carried in said housing for operating said second reset button so as cause said second counter to be reset to the zero setting thereof, said second actuating means including a follower operable in response to rotation of said second cam whereby said second counter is reset only upon alternate manipulations of said operator, the actuating sectors of said first and second cams being 180* out of phase with one another whereby successive manipulation of said manual operator effects alternate resetting of said first and second counters, a third cam mounted on said shaft for rotation therewith and including alternate actuating sectors and dwell sectors, each of said actuating sectors and dwell sectors defining a cycle of operation equivalent to the angular extend of rotation of said shaft, and a switch carried in said housing and connected to the output of said frequency dividing means, said switch being alternately operable in response to rotation of said third cam between a first position wherein said switch applies said train timing pulses to said first counter and a second position wherein said switch applies said train of timing pulses to said second counter, the actuAting sectors of said first cam and said third cam being substantially in phase with one another so that operation of said shaft concurrently causes said first counter to be reset and said switch to operate to the first position thereof so as to cause said train of timing pulses to be applied to said first counter and upon a subsequent operation of said manual operator said third cam causes said switch to operate to the second position thereof wherein said train of timing pulses is applied to said second counter and concurrently said second cam causes a said second actuating means to operate so as to reset said second counter, whereby the user of the timing system may take a reading of the elapsed time from the indicator output of the first counter while the second counter is operated and whereby successive manipulation of said operator causes said first counter to be reset and said switch to move to said first position thereof to effect operation of said first counter while said second cam rotates through a dwell portion thereof so as to the user to take a reading of elapsed time from the indicator output of said second counter.
 11. A portable writing board comprising a flat board having a size and shape to be conveniently supported upon a limb of the user and adapted to receive paper thereon for writing purposes, timing apparatus comprising a battery operated electrically energized clock mounted on said board for producing a train of timing pulses at an output thereof, a first timing pulse counter mounted on said board and including an input and an indicator output, a second timing pulse counter mounted on said board and including an input and an indicator output, frequency dividing circuit means including electronic switch means operative to prevent application of said train of timing pulses to either of said impulse counters when the battery voltage applied to said circuit is less than a predetermined value coupled to said clock and responsive to the train of timing pulses to reduce the frequency of said train of timing pulses to a second predetermined frequency at an output therefor, and switching apparatus mounted on said board for connecting said timing apparatus output alternately to the input of said first counter and the input of said second counter, said switching apparatus alternately coupling said frequency dividing circuit means to one of said pulse counters for translating said train of timing pulses thereto whereby the indicator output of said counter operates at said second predetermined frequency, said switching apparatus including a manual operator effective when operated by the user of the writing board to apply the train of timing pulses alternately to one or the other of the inputs, whereby said counters are driven alternately by said timing apparatus. 